A team of physicists led by Stephen Jardin of the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) has discovered a mechanism that prevents the electrical current flowing through fusion plasma from repeatedly peaking and crashing. This behavior is known as a “sawtooth cycle” and can cause instabilities within the plasma’s core. The results have been published online in Physical Review Letters. The research was supported by the DOE Office of Science. Read more
- PPPL physicists find clue to formation of magnetic fields around stars and galaxies
- Physicists are a new kind of superhero in comic book on fusion energy
- PPPL to design a high-resolution diagnostic system for the National Ignition Facility
- PPPL scientists unveil their latest results at the 57th annual meeting of the American Physical Society Division of Plasma Physics
As a collaborative research institution, PPPL works closely with leading research centers throughout the country and around the world. Now a collaboration between scientists at the University of Michigan and PPPL has shown how the process that underlies solar flares and the northern lights can take place in fusion experiments through a surprising new mechanism.
The process, called magnetic reconnection, occurs when the magnetic field lines in hot, charged plasma gas come together and violently snap apart. Such reconnection takes place in plasmas throughout the universe.
In a recent paper in Physical Review Letters, the researchers used computer modeling to uncover how reconnection also can occur in the very hot and very dense plasmas created by laser compression of pellets of hydrogen fuel. Such plasmas are used for inertial confinement fusion (ICF), which represents an alternative form of experimentation to the magnetic-confinement fusion studied at PPPL.
A unique feature of ICF is that the magnetic field lines that produce reconnection can be carried by flows of heat, rather than flows of mass. “Essentially, what we found is a completely new magnetic reconnection mechanism,” said Alexander Thomas, assistant professor of nuclear engineering and radiological sciences at the University of Michigan and lead author of the paper. Joining Thomas in the work was Archis Joglekar, a Michigan doctoral student in nuclear engineering and radiological sciences.
PPPL contributions to the study came from Amitava Bhattacharjee, head of the Theory Department at PPPL and a Princeton University professor of astrophysical sciences, and PPPL physicist Will Fox.
(Above: This poster with cutouts shaped like a light bulb and letters was used to signal successful fusion shots to observers on Dec. 9, 1993)
The fascinating science that is at the heart of everything at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) keeps hundreds of staff members busy. For the past week or so, though, with the approach of a major anniversary, Lab matters have seemed especially charged.
On Dec. 9, 1993, a team of researchers at PPPL produced world record-breaking levels of fusion energy in a one-of-a-kind experimental device called the Tokamak Fusion Test Reactor (TFTR). I was on-site, too, not as a member of the Lab staff, but as a science reporter for The Star-Ledger of Newark, New Jersey’s largest newspaper.
On that long ago evening at PPPL, I had serious competition. I was one of a handful of reporters who had shown an interest in PPPL for some time who was invited to cover the event. Others in the general press would be drawn by our stories and a public television video to cram into a news conference the next day for this world-class story. I stood in the main lobby of the Lab’s main administration building and met two other reporters, and we moved to the auditorium to wait for news from the TFTR control room. A monitor in the auditorium displayed images of activity from the packed control room via a camera located there. Ron Davidson, PPPL’s director at the time, and Dale Meade, then the Lab’s deputy director, gave animated play-by-plays to the auditorium audience of what could be seen on the television interspersed with viewgraphs on fusion. In addition to the press, staff members of PPPL – some of whom brought their children – perched there, taking it in.
The late Malcolm Browne of the New York Times was covering the experiment. He had earned a Pulitzer Prize in 1964 for his bulletins from the Vietnam War. When I met him that evening, he was enjoying a grand second act as a front-page science writer. He was quiet and nice. I also spoke as we worked with Boyce Rensberger of the Washington Post. His book, How the World Works, with its deft explanations of formidable concepts such as Einstein’s theories of relativity and the field of quantum mechanics, made it a go-to source for science writers. He was outgoing and nice.
Any story from this event loomed as a wonderful capper for my year – one already loaded with stories of worldwide interest. In June 1993, eight years into my stint as my newspaper’s science editor, I wrote about Princeton Professor Andrew Wiles’ wondrous announcement that he proved a 300-year-old math problem known as Fermat’s Last Theorem. And, on October 13, 1993, only two months before the fusion experiment, I trailed Princeton Professor Joseph Taylor the day the Royal Swedish Academy of Sciences awarded the Nobel Prize in physics to Taylor and Russell Hulse. Hulse was a former graduate student of Taylor’s who had risen to be a physicist at PPPL. They were honored for their 1974 discovery of a new type of pulsar, a find that opened up new possibilities for the study of gravitation.
On that night at PPPL, I was on edge. I knew I could report and write the story. The problem rested with my computer. The newspaper was experimenting with portable computers in those days and my model was a doozy. Static electricity brought about by a movement as slight as a shuffle on an office carpet provoked tremors in the casing and blackouts on the screen. Even if you managed to write a story and hold on to it, the device’s manual phone hook-up – a black plastic molded doodad that fit very imperfectly on an end of the handset of a standard rotary telephone – worked erratically.
I also stewed over the fact that I knew many of the scientists involved in this experiment. I liked them. Journalists are supposed to be emotionally removed so they can fully represent the public interest and report objectively. In my heart, I realized, I was rooting for the PPPL team.
The reporters covering the event had editors waiting at other ends of the phone line who expected a full-fledged news story as soon as a breakthrough was achieved. We all worked for morning newspapers with tight evening deadlines. As the hours wore on, my colleagues remained calm. In my case, jubilation and tension battled for control of my emotions. I looked forward to the possibility that the researchers would pull it off and worried about the opposite outcome. I dreaded using my computer. We wondered aloud whether the results would be announced in time for us to report them. To pull off writing such a complex story at the verge of the newspaper’s print deadline, each of us had composed “A matter” – the background material that gives the story context – ahead of time. From time to time, we scurried to different corners of the lobby and worked so that when the news came, all we would need would be the lede (the first sentence or, sometimes, paragraph) and a quote. I, for one, did not want to have to explain the intricacies of a fusion reaction on the fly!
Twice I watched the A-matter I had written on my computer disappear as if the words had been written in smoke. The third version held. Just in time for deadline, as if the research team had been prompted, the scientists achieved their record.
It took me two attempts to successfully send my story over a telephone. The transmission hissed and twanged, my words transferred in stages to bits, electronic pulses and sound waves. The story relayed a remarkable scientific achievement. I knew I had spread the word to hundreds of thousands of readers. Now they would know.
I was exhausted from the cliffhanger evening. I was happy for the scientists.
We made our deadlines. And we all made the front page.
Fusionista Kitta MacPherson is the director of communications at the Princeton Plasma Physics Laboratory and an award-winning science writer.
PPPL’s MINDS Team
Fusion and its spinoffs are so fascinating, it’s easy to imagine why these subjects can so easily capture the public imagination. Sheldon has been known to talk magnetic fusion on CBS-TV’s The Big Bang Theory and the National Ignition Facility’s inertial confinement laser complex was featured in the recent “Star Trek Into Darkness.”
Now, a technology that engineers from the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (shown in top photo) developed from basic research, a nuclear detection system called MINDS, has figured at the center of an episode of NCIS-Los Angeles. Episode 8, titled “Fallout,” continued the show’s consistent plot pattern of pitting a crack crew of investigators against evildoers. The show, its title an acronym of “Naval Criminal Investigative Service,” offers a potent brew that combines the genres of police detective story and military drama. The series premiered on the CBS network in 2009.
Meredith Jacobs, writing about the Nov. 12 episode on examiner.com, an online entertainment news site, reported that a bad guy in the episode accessed a computer at the U.S. Department of Energy and obtained the locations of MINDS devices. “If terrorists knew where those devices were, they’d know where to transport bombs,” Jacobs wrote. The storyline develops to involve stolen federal secrets, international relations with Russia, and a chase to recover computer drives. In the end, the champions of good, the NCIS team, triumph and the secrets of MINDS are secured.
“It is nice to know that MINDS as featured on the NCIS-LA show now joins the ranks of other fusion-related technologies that have appeared in Spider Man, Iron Man, and Star Trek,” said Charles Gentile, who led the development of MINDS at PPPL with a team of engineers and was delighted to hear of MINDS’ television debut. “Clearly the imagination of Hollywood is intrigued with fusion technologies.”
I wrote about MINDS for the first time in 2009 when I worked as the science writer for Princeton University’s Office of Communications. I remember the dramatic story related by the team of how the complex technology was developed over many years. The “Miniature Integrated Nuclear Detection System” (MINDS) was created by the engineers while working on decommissioning the Tokamak Fusion Test Reactor, PPPL’s legendary experimental device that produced world records for fusion and high temperatures. After 9/11, the developers of MINDS realized the techniques they had developed for determining the identity and amount of extremely minute levels of elements in TFTR could be used as a defensive measure to detect and identify nuclear materials. The simple, portable device identifies materials through their characteristic energy signals, as unique as fingerprints and is now used in ports and transportation hubs to protect the public.
At the time I was first writing about MINDS, John Ritter, director of Princeton University’s Office of Technology Licensing and Intellectual Property, told me: “This technology may provide a method to protect the public from different kinds of threats. Viewed from that standpoint, we are very excited about MINDS.”
It is also exciting to know that Hollywood gets it, too.
Fusionista Kitta MacPherson is the director of communications at the Princeton Plasma Physics Laboratory and an award-winning science writer.
By John Greenwald
How crucial is PPPL to the worldwide effort to develop fusion as clean and abundant source of energy for generating electricity? The full extent of the Laboratory’s role came home to me this week at the annual meeting for fusion communicators held at the headquarters of ITER, the huge international project under construction in Cadarache, France, to demonstrate the feasibility of fusion energy.
Looking around the meeting room at communicators from the countries that participate in ITER—China, Japan, India, South Korea, Russia, the European Union and the United States—I realized that PPPL has scientific partnerships with virtually all of them. This is true whether the Laboratory is building components and conducting research relevant to ITER, or contributing design and engineering know-how to a next-step fusion facility envisioned by South Korea.
It was thus no coincidence that I happened to bump into PPPL physicists Rob Goldston and Dave Gates in the lobby of ITER headquarters. Both came as members of international groups that provide expert scientific advice to ITER, leaving little doubt that PPPL is a key player in the global quest to develop fusion.
Mark your calendar and prepare to have some fun at The Princeton Plasma Physics Lab’s Open House on June 1 from 9 a.m. to 4 p.m. when the Laboratory will open its doors for the public to see the National Spherical Torus Experiment and other research experiments. Come take a self-guided tours, take part in hands-on activities, watch demonstrations. Plans also include a moon rocks display from NASA, lectures on fusion by PPPL Director Stewart Prager, a cryogenics show, firefighting demonstrations and numerous other activities as well as refreshments and give-aways.
Princeton Plasma Physics Laboratory
100 Stellarator Road
Princeton, NJ, 08540
FUSIONISTA: FUSION IN POP CULTURE
Greg Hammett, a physicist at the Princeton Plasma Physics Laboratory, was minding his own business one recent evening, chilling, watching a TV show popular with Lab folks and many others – the top-rated CBS comedy, The Big Bang Theory (Episode14, titled “The Cooper-Kripke Inversion”.) Suddenly he saw it: Jim Parsons, the actor playing one of the show’s lead characters – a brilliant, though socially awkward theoretical physicist named Sheldon Cooper – was at work in front of a whiteboard. Scrawled across the board in red-orange magic marker were letters and digits representing an idea that Hammett knew quite well. To his great pleasure, Hammett spied an equation he had helped derive in his research on fusion energy. “This equation describes turbulent diffusion in fusion devices and also describes how performance can be improved by sheared flows that can reduce the turbulence,” Hammett said. “The ovals at the bottom of Sheldon’s whiteboard are meant to illustrate this stabilization mechanism – which we are studying as a possible way to improve fusion reactors – and this is an illustration that I’ve used in my talks.”
|PPPL Physicist Greg Hammett|